Electrical System SGR
AC power is converted to 28V DC power by three Transformer
Rectifiers to supply DC power to DC Bus 1 and DC Bus 2.

  • DC Bus 1 is powered by TR 1 and backed up by TR 2 and TR 3.

  • DC Bus 2 is powered by TR 2 and backed up by TR 1 and TR 3.

  • If power to TR 2 is lost, the TR 3 Transfer Relay shifts and TR 3
    receives power from Transfer Bus 1.

  • The Battery Bus is powered by TR 3 and backed up by the
    Battery. TR 3 is normally backed up by TR 2 or alternately by
    TR 1 through the TR 3 Transfer Relay.

  • The  Switched Hot Battery Bus and Hot Battery Bus are powered
    by the Battery/Battery Charger.

  • A DC Cross Bus Tie Relay isolates DC Bus 1 from DC Bus 2 at
    Glide Slope capture during an Autopilot ILS or Flight Director
    approach.
Electrical System Overview

  • Generators ON
  • Bus Transfer switch in AUTO

AC Power
DC Power
Standby Power